Yikes! This is not just IAD-YTZ! According to the Porter site, its system wide:
We are experiencing system wide network outages affecting our website, Call Centre, reservation system and flight planning. Thank you for your patience while we work to provide updates.
The following flight numbers have been cancelled. If your flight number is on this list, please do not go to your departure airport. Our Call Centre team is expecting your call at 1-888-619-8622. We are expecting a high volume of calls and thank you for your patience.
For all other passengers scheduled for departure today, we hope to provide updates as soon as we are able.
Nous regrettons de vous informer que nous éprouvons présentement des difficultés techniques qui touchent de multiples lignes aériennes.
Notre site Web, notre centre d'appels ainsi que notre système de réservations central sont touchés.
Nous vous reviendrons sous peu et nous sommes désolés de tous inconvénients.
Last updated 21:35 EST, Sept. 17, 2013
Cancelled flights, evening of Tuesday, September 17, 2013
Flight # From To
937 Toronto Boston
938 Boston Toronto
936 Boston Toronto
389 Toronto Chicago
384 Chicago Toronto
611 Toronto Timmins
612 Timmins Toronto
128 New York Toronto
415 Toronto Montreal
422 Montreal Toronto
727 Toronto Washington DC
728 Washington DC Toronto
273 Toronto Ottawa
274 Ottawa Toronto
Flight # From To
275 Toronto Ottawa
276 Ottawa Toronto
277 Toronto Ottawa
615 Toronto Timmins
616 Timmins Toronto
637 Toronto Thunder Bay
638 Thunder Bay Toronto
946 Toronto Boston
947 Boston Toronto
948 Toronto Boston
949 Boston Toronto
426 Toronto Montreal
427 Montreal Toronto
428 Toronto Montreal
Flight # From To
429 Montreal Toronto
434 Toronto Montreal
433 Montreal Toronto
539 Toronto Sudbury
540 Sudbury Toronto
577 Toronto Windsor
578 Windsor Toronto
579 Toronto Windsor
391 Toronto Chicago
392 Chicago Toronto
143 Toronto New York
144 New York Toronto
617 Toronto Timmins
Cancelled flights, morning of Wednesday, September 18, 2013
Flight # From To
245 Toronto Ottawa
610 Timmins Toronto
572 Windsor Toronto
242 Ottawa Toronto